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While frying and baking are both common culinary ways to use white potatoes (Solanum tuberosum) and sweet potatoes (Ipomoea batatas), when it comes to growing these plants, they are completely different. The climate, soil conditions, pests, diseases and length of time until harvest all separate these two vegetable crops from each other. Understanding the requirements for each plant, you can determine the best option for your garden.

Climate

The climate required for growing sweet potatoes is nearly opposite of that needed for white potatoes. Sweet potatoes are a hot summer crop, growing best when daytime temperatures range from 75 to 95 degrees Fahrenheit. White potatoes need a cooler climate with temperatures between 45 and 80 F for the duration of the growing season.

Soil Requirements

The type of soil used for growing both sweet potatoes and white potatoes is almost the same, with some subtle differences. White potatoes need acidic, sandy, well-drained soil. The best pH for white potatoes is between 5.8 and 6.5. Acidic soil is needed to prevent a potato disease called scab, which appears as pitting of the potato's skin. However, soil that is too acid will reduce your potato crop yield. Sweet potatoes need a similarly acidic soil. They thrive in soil with a pH of 5.8 to 6.2, but you can still grow sweet potatoes if your soil is between 5.0 and 5.7 pH. Soil for sweet potatoes should be well-drained and loamy.

Diseases and Pests

The problems faced by sweet potatoes and white potatoes are not the same. Sweet potatoes are most susceptible to fungal diseases, root rot, sweet potato weevils and wireworm. Planting disease-resistant sweet potato varieties and keeping your garden free of weeds will help avoid these problems. White potatoes are plagued by Colorado potato bugs, leafhoppers, flea beetles, scab, aphids and blight.

Time Until Harvest

Sweet potatoes take 100 to 150 days to reach the point they are ready for harvest. You will be able to see this from the color of the vines, which turn yellow and shrivel when it's time to harvest the sweet potatoes. The time to harvest white potatoes depends on the variety. Early season potatoes require the shortest growing season of just 70 to 90 days. Potatoes for harvest in midseason require 90 to 135 days, and the longest growing potatoes stay in the ground for 135 to 160 days.